const mongoose = require("mongoose");
mongoose.connect("mongodb://127.0.0.1:27017/cows");
mongoose.connection.on("connected",()=>{
    console.log("数据库连接成功");
})
mongoose.connection.on("disconnected",()=>{
    console.log("数据库连接断开");
})
mongoose.connection.on("error",()=>{
    console.log("数据库连接失败");
});
module.exports = mongoose;